U.S. patent application Ser. No. 06/208,734 now U.S. Pat. No. 4,370,012 describes and claims a multi-contact connector for single sided substrates (having terminal pads on only one side which are contacted by the connector terminals) of the zero insertion force type. Connectors in accordance with the above identified U.S. application can be constructed with the terminals on closely spaced centers and are capable of accommodating a relatively large number of terminals. A connector in accordance with the above identified application has an insulating housing which contains the terminals in side-by-side relationship with the contact portions of the terminals extending beyond one surface of the terminal housing. The substrate is clamped against the surface of the housing by a clamping means so that the terminal pads on the substrate electrically contact the contact portions of the terminals. The clamping means for clamping the substrate against the housing comprises a cam which extends beside the housing and which, upon rotation, urges the substrate against the housing.
A connector in accordance with the above identified application has a formed metallic frame and a separate formed spring on the frame which cooperate with the cam shaft to provide the clamping means for the substrate. It would be desirable to provide a clamping means of simplified construction, as compared with the clamp shown in U.S. Pat. No. 4,370,012, in order to improve the reliability and decrease the cost of the connector. It would further be desirable to provide a force multiplier for the clamp which would permit placement of substrates in connectors and removal of the substrates without the aid of an additional tool. It is also important that connectors of the type shown in the above identified application be capable of being placed on a circuit board in closely stacked relationship and that the substrates be individually removable from the connectors in the stock. The present invention is, in general, directed to the achievement of these improvements to connectors of the type shown in the above identified U.S. Pat. No. 4,370,012.
A zero insertion force electrical connector in accordance with the invention is of the type comprising a terminal housing having a plurality of terminals in the housing, the terminals having contact portions which normally extend beyond a first surface of the terminal housing. The connector has a clamp for clamping a substrate or the like against the first surface of the housing so that terminal pads on the substrate will electrically contact the contact portions of the terminal. A connector in accordance with the invention is particularly characterized in that the clamp comprises a clamping bar which extends parallel to, and is spaced from, the one surface of the terminal housing, the clamping bar being movable parallel to its axis between first and second positions. A guide is provided which is effective between the clamping bar and the terminal housing and which moves the clamping bar laterally of its axis towards the first surface of the terminal housing when the clamping bar is moved from the second position to the first position and which moves the clamping bar away from the first surface when the clamping bar is moved from the first position to the second position so that upon placement of edge portions of the substrate between the clamping bar and the first surface of the terminal housing when the clamping bar is in the second position and upon thereafter moving the clamping bar to the first position, the substrate will be clamped against the first surface of the housing and the terminal pads on the substrate will be pressed in against the contact portions of the terminals.
In accordance with a further embodiment, a force multiplying actuator is provided for moving the clamping bar between the first and second positions. In accordance with a further embodiment, the terminal housing is supported in a frame which has guide portions which extend beside the first surface of the terminal housing at the ends of the housing. The guide comprises pin-slot connections between the clamping bar and the guide portions portions of the frame. In accordance with a still further embodiment, the guide is resiliently deformable to permit variation of the position of the clamping bar when the clamping bar is in the first position whereby the connector can be used with substrates of varying thickness. In accordance with further embodiments, the force multiplying actuator comprises a rotary cam mounted adjacent to one end of the terminal housing, the clamping bar having an extension which surrounds the cam so that upon rotation of the cam, the clamping bar is moved between the first and second positions. In accordance with further embodiments, the cam comprises a cylindrical body having an eccentric pin extending therefrom which is received in a slot in the surface on an adjacent section of the housing so that rotation of the cylindrical body causes lateral movement thereof and movement of the clamping bar. In accordance with a still further embodiment, the force multiplying actuator has a handle extending therefrom by means of which it is operated, the handle being inclined in a manner such that it will nest with handles extending from the forced multipliers of adjacent connectors.